Shock resistant mountings for light bulbs

ABSTRACT

A lamp includes a housing and a socket adapted to receive a light bulb, the latter being suspended from the housing by shock resistant mounting means comprising arms each having rigid points of connection formed integral with the housing and the socket, the arms being integral with the housing and the socket and extending therebetween with the arms each being fabricated of a strip of material formed into a corrugated and having a plurality of corrugations.

United States Patent Magi [151 3,666,940 [451' May30, 1972 [54] SHOCK RESISTANT MOUNTINGS FOR LIGHT BULBS [72] Inventor: Hugo Magi, Etobicoke, Ontario, Canada [73] Assignee: Dominion Auto Accesories Limited, Toronto, Ontario, Canada [22] Filed: Apr. 27, 1970 [21] App]. No.: 32,084

Related US. Application Data [63] Continuation-impart of Ser. No. 809,315, Mar. 21,

1969, Pat. No. 3,564,483.

[52] US. Cl ..240/90, 248/204, 313/50 [51] Int. Cl. ..F21v 15/04, l-lOlj 5/48 [58] Field of Search ..240/90, 58, 153; 248/358, 18', 248/204; 313/50, 269; 267/160 [5 6] References Cited UNITED STATES PATENTS 3,300,636 1/1967 Quellandetal .....240/90 1,295,316 2/1919 Hines ..267/160 X 3,327,1 10 6/1967 Baldwin ..240/90 1,313,739 8/1919 Ryerson ..240/90 FOREIGN PATENTS OR APPLICATIONS 21,419 7/1914 Great Britain ..267/160 Primary Examiner-Richard C. Queisser Assistant Examiner-Ellis J. Koch Attorney-Sim & McBumey ABSTRACT A lamp includes a housing and a'socket adapted to receive a light bulb, the latter being suspended from the housing by shock resistant mounting means comprising arms each having rigid points of connection formed integral with the housing and the'socket, the arms being integral with the housing and the socket and extending therebetween with the arms each being fabricated of a strip of material formed into a corrugated and having a plurality of corrugations.

9 Claims, 2 Drawing Figures Patented May 30, 1972 INVENIUR. HUGO MAGI SHOCK RESISTANT MOUNTINGS FOR LIGHT BULBS This is a continuation-in-part of application Ser. No. 809,315, filed Mar. 21, 1969 now US. Pat. No. 3,564,483.

This invention relates generally to lamps, and, more particularly, to shock resistant mountings for the bulbs of such lamps.

Many difi'erent types of lamps, for example, signal and other types of lamps used on motor vehicles, are subject to vibrations and shocks. Unless the light bulbs of such lamps are in some way protected from these shocks and vibrations, the light bulbs may fail prematurely. To this end many different types of so-called shock-free" or shockproof bulb mountings have been designed, and typical of these are those shown in US. Pat. Nos. 3,300,636, L.l-I. Quelland et al., issued Jan. 24, 1967, and 3,327,110, G.D Baldwin, issued June 20,

Prior art shock resistant bulb mountings generally attempt to cushion the light bulbs by damping vibrations before they are imparted to the bulbs, and varying degrees of success utilizing this approach have been obtained. One problem with such an approach is that there is a tendency for the bulbs to be permitted too high a degree of movement, which can result in displacement of the bulb from the location that it should be in relative to the lens of the lamp. On the other hand, restraining the degree of movement permitted severely limits the shock resisting capabilities of the bulb mounting.

In accordance with this invention there is provided a shock resistant mounting for a lamp bulb designed so that high frequency shocks or vibrations, which are the ones that can cause damage to the filaments of light bulbs, are converted to less damaging low frequency vibrations, the construction of the mounting being such that movement of the light bulb supported by the mounting is within optically acceptable limits.

This invention will become more apparent from the following detailed disclosure, taken in conjunction with the appended drawings, in which:

FIG. 1 is a perspective exploded view of part of a direction signal lamp having a shock resistant bulb mounting embodying the instant invention; and

FIG. 2 is a front elevation, partly broken away and partly in section, showing in greater detail a part of the lamp shown in FIG. 1.

While this invention will be described herein as used in a direction signal lamp for a motor vehicle, this is strictly by way of example and is not intended to be limiting.

Referring to the drawings, a direction signal lamp includes a housing 10 made of electrically insulating material, e.g., a suitable synthetic polymeric material such as LEXAN" (a trade mark for apolycarbonate resin), to which is fastened by any suitable means lenses 11. Only one lens 11 is shown, but it will be understood that an identical lens will project forwardly from the front of housing 10 being mounted on the rim 12 thereof. Lenses 11 are transparent or translucent and may be colored or plain. Generally one lens will be red and the other amber for a direction signal lamp. Lenses 11 may have semicircular flanges thereon that snap into mating grooves in rims 12, or O-rings may be employed between lenses 11 and rims 12.

Projecting inwardly from rim 12 but formed integral therewith and constituting a part of housing 10 is a strengthening partition 13 in which is provided a recess 14 that is occupied by the light bulb (not shown) of the lamp.

The light bulb may be a conventional single filament bulb with a bayonet type base, although a bulb with a screw-in type base could be employed, and when mounted in the bulb socket to be hereinafter described, its filament is directly aligned with the optical centers of lenses 11, which may be socalled bulls-eyes, for example.

Located below recess 14 and held in position by shock resistant members 15 to be described hereinafter in detail and which are formed integral with partition 13 is a light bulb socket 16. Part 16a of socket 16 is formed integral with the supports 15 and thus is fabricated of plastic, if this is the material used for housing 10. The other part 16b of socket l6 constitutes one contact for one terminal of the light bulb of the lamp and is made of metal. As may be seen by reference to the drawings, socket 16 is of the bayonet type, but obviously could be of the type to receive a screw-in bulb. The other contact 17 of socket 16 is conventional being an electrical contact disposed in or on a disc 18 of electrically insulating material that is biased upwardly by a spring 19.

Formed integral with housing 10 and depending downwardly therefrom is a hollow, threaded stem or stud 20. Stud 20 has an open channel 21 formed therein. Located in channel 21 is a metal ground strap 22 that is electrically connected to socket part 16b and the other end of which is hooked over the end of stud 20.

In the manufacture of the lamp shown in the drawings, the hooked end of ground strap 22 is inserted through an opening 23 in housing 10 that registers with channel 21, strap 22 is positioned in the channel, and the hooked end of the ground strap is hooked over the end of stud 20. The rectangular end portion 24 of ground strap 22 then is positioned in a recess 25 fonned for it in socket part with the stud 26 extending through the opening 27 formed in end portion 24, stud 26 being formed integral with socket part 16a. Socket part 16b then is mounted on socket part 16a with the studs 26 and 28 of socket part 160 projecting through openings 29 and 30 fonned in cars 31 and 32 of socket part 16b. After this has been done, socket part 16b and ground strap 22 are physically secured together and positively electrically connected, as by ultrasonic welding. When this has been accomplished, studs 26 and 28 are melted over cars 31 and 32 to form caps that hold socket part 16b in place. Of course, during the assembly of socket 16, spring 19, contact 17 and disc 18 are located within the socket and the insulated conductor 33 that is soldered or otherwise connected to contact 17 is passed through opening 34 in housing 10 and brought out of the lamp via hollow stem 20.

As best shown in FIG. 2, the depth of channel 21 preferably is such that the two edges 35 and 36 (FIG. 1) of ground strap 22 extend above the roots of the threads on stem 20. This ensures positive grounding of the lamp. In this regard, as best seen in FIG. 2, reference numeral 37 designates a grounded part, say the fender, of a motor vehicle. In mounting the lamp on the fender, stem 20 is inserted through an opening in'the fender, an electrically conductive washer 38 is placed over stem 20 and an electrically conductive nut 39 is screwed'onto' stem 20 and tightened. The threads on nut 39 will bite into edges 35 and 36 of ground strap 22 and, when the nut has been tightened, grounding of the lamp will be effected automatically via ground strap22, nut 39, washer 38 and fender 37.

The grounding means hereinbefore described are not per se a part of this invention but are described and claimed in copending application Ser. No. 809,315, filed Mar. 21, 1969, now US. Pat. No. 3,564,483 for Signal Lamp with Built-In Ground Strap" and assigned to the assignee of this invention.

The shock resistant mounting of this invention consists of arms 15 that are of generally sinusoidal or corrugated configuration, each having a plurality of corrugations, and that are molded integral with partition 13 of housing 10 and part 160 of socket 16, the arms being rectangular in cross-section and fabricated of strips with a width dimension considerably greater than the depth dimension thereof. Arms 15 have a common axis and extend from diametrically opposite sides of socket 16. The arms are oriented so that the convolutions or undulations thereof are in the vertical plane, i.e., a plane parallel to the longitudinal axis of socket 16. With the arms so oriented, a limited degree of up and down movement of socket 16 in the vertical plane is permitted with flexure taking place at the peaks of the convolutions. A limited degree of side-toside movement in the vertical plane with compression and expansion of the convolutions also is permitted.

The convoluted configuration of arms 15 coupled with the limited degree of compressibility and expansibility thereof makes the arms what could be referred to as frequency converters. High frequency vibrations are reflected from the walls that define arms 15, and the movement of these walls as arms l5 flex lowers the frequency of these vibrations so that they are relatively low frequency and relatively harmless vibrations by the time that they are imparted to socket 16. The greater the number of convolutions, the greater will be this frequency conversion effect, but, on the other hand, care must be taken to avoid using so many convolutions that extensive up and down and side-to-side movement ofsocket 16 is permitted.

It is highly desirable that each arm be connected to part 16b of socket 16 as high up on socketl6 as possible, since the closer this connection is to the filament of the bulb supported by socket 16, the shorter is the radius of curvature described by the filament as the bulb moves back and forth out of the vertical plane, so the smaller is the chance of the bulb becoming out of focus with respect to lenses 11 as a result of such movement. Thus arms 15 are connected to part 16a of socket 16 adjacent the open end thereof and at the positive" peaks of the corrugations. For the same reason, attachment of arms 15 to partition 13 at the lowermost point or negative peaks of arms 15 is desirable. 1

it should be noted that with the construction of arms 15 shown and described, a shock resistant mounting that is formed integral with the lamp and the socket, which is simple and inexpensive to fabricate, and yet which permits limited movement in two perpendicular directions and even more limited movement in a third direction perpendicular to the other two is obtained without any pivot pins being required, the points of connection of arms 15 to the socket and hous'mg being rigid and integral with the socket and housing.

What I claim as my invention is:

l. A lamp comprising a housing; a socket adapted to receive a light bulb; and shock resistant mounting means comprising first and second arms each having rigid points of connection fonned integral with said housing and said socket, said arms being integral with said housing and said socket and extending therebetween to suspend said socket from saidhousinmsaid arms each being fabricated of a strip of material of greater width than thickness and being formed into a corrugated configuration which includes a plurality of corrugations, the plane in which the corrugations of said corrugated strips undulate being parallel to the longitudinal axis of said socket and perpendicular tosaid width of said corrugated strips.

2. A lamp according to claim 1 wherein the corrugations of said corrugated strips have positive" and negative peaks and wherein said socket has an open end for reception of a light bulb, said points of connection of said arms and said socket being at positive" peaks of said corrugations and being adjacent said open end.

3. A lamp according to claim 2 wherein said points of connection of said arms and said socket are at negative peaks of said corrugations.

4; A lamp according to claim 1 wherein said housing, said,

arms and at least the part of said socket connectedto said arms are formed of a synthetic polymeric material.

5. A lamp according to claim 1 wherein said strips are rectangular in cross-section.

6. A lamp according to claim 1 wherein said arms lie on a common axis and extend from diametrically opposite positions on said socket.

7. A lamp according to claim 2 wherein said arms lie on a common axis and extend from diametrically opposite positions on said socket.

8. A lamp according to claim 7 wherein said strips are rectangular in cross-section.

9. A lamp according to claim 8 wherein said housing, said arms and at least the part of said socket connected to said arms are formed of a synthetic polymeric material.

III i I! 

1. A lamp comprising a housing; a socket adapted to receive a light bulb; and shock resistant mounting means comprising first and second arms each having rigid points of connection formed integral with said housing and said socket, said arms being integral with said housing and said socket and extending therebetween to suspend said socket from said housing, said arms each being fabricated of a strip of material of greater width than thickness and being formed into a corrugated configUration which includes a plurality of corrugations, the plane in which the corrugations of said corrugated strips undulate being parallel to the longitudinal axis of said socket and perpendicular to said width of said corrugated strips.
 2. A lamp according to claim 1 wherein the corrugations of said corrugated strips have ''''positive'''' and ''''negative'''' peaks and wherein said socket has an open end for reception of a light bulb, said points of connection of said arms and said socket being at ''''positive'''' peaks of said corrugations and being adjacent said open end.
 3. A lamp according to claim 2 wherein said points of connection of said arms and said socket are at ''''negative'''' peaks of said corrugations.
 4. A lamp according to claim 1 wherein said housing, said arms and at least the part of said socket connected to said arms are formed of a synthetic polymeric material.
 5. A lamp according to claim 1 wherein said strips are rectangular in cross-section.
 6. A lamp according to claim 1 wherein said arms lie on a common axis and extend from diametrically opposite positions on said socket.
 7. A lamp according to claim 2 wherein said arms lie on a common axis and extend from diametrically opposite positions on said socket.
 8. A lamp according to claim 7 wherein said strips are rectangular in cross-section.
 9. A lamp according to claim 8 wherein said housing, said arms and at least the part of said socket connected to said arms are formed of a synthetic polymeric material. 